Operation de-rag

Description:Clogged pumps, a.k.a. ragging, costs the industry millions of dollars and increases the risk to worker safety. There is a variety of technologies to combat these pesky rags, including in-line grinders that grind rags to a pulp, pumps that chop, slice, and dice, and an array of screw pumps and special impellers designed to pass the rags through. Deciding how to approach the problem of ragging is a difficult one, often dictated by cost and level of complication. This was the case at Metro Vancouver's Baynes Rd Pump Station. Operators were de-ragging several times a week, sometimes during the night and on weekends. The culprit? Mostly wet-wipes and fabrics that clump together and form an impassable ball of knotted material. We wanted a solution that would reduce the number of call-outs and require little to no change to infrastructure. Grinders and specialized pumps would require new discharge piping, power upgrades, and alterations to the building structure. Instead, we retrofitted an existing pump with a new "ripping" impeller, requiring no major changes. Unlike a chopping pump, this impeller rips rags apart as they pass through the volute. So far, its performance is impressive. With the new impeller, the pumps have ragged only once within 6 weeks.